Compared to other cities, Austin has very lenient laws regarding the homeless population. As well as a great collection of organizations working as resources for people trying to get back on their feet. That is a very attractive motive for the homeless and travelers. Also people in Austin tend to be very friendly and more accustomed to dealing with strange folks. A few years back Austin did try to implement a bulked up aggressive panhandling law, although I think it did not go through. Being the liberal center in a mostly conservative state as well as home to a large amount of state offices and non-profit organizations, there is more options in Austin than anywhere else in the state.
I work on East Riverside and homeless has been a big issue for years. However, within the last two years there has been a steep decline of problematic(on drugs) homeless folks.
Sat out on the lawn at palmer and watched all the cranes working on our city of progress. Quite the future we have in store.